Horizontal counterflow film fill is recognized as an effective way to cool liquid, typically water, in a cooling tower. The water is sprayed onto the film fill which may be formed of spaced connected vertical sheets on which the water spreads out for more efficient cooling by upwardly flowing air. The air enters inlets in the lower portion of the tower flowing in a generally horizontal direction and is drawn upwardly into a vertical direction, typically by a fan mounted in a stack above the film fill or by the draft effect of a tall stack or chimney. The vertically flowing air cools the counterflowing gravitating water flowing through the film fill. One problem with this system is that there is an uneven distribution of the air due to the varying air resistance below the film fill in an inboard direction as the air turns upwardly. There is a natural tendency for the air to avoid the long route into the central portion of the tower. This leads to unequal cooling of the liquid in the film fill. Another source of inefficiency in this system is that there is little cooling which occurs below the film fill because the water tends to gravitate in concentrated streams leading to inefficient air liquid contact. One approach to improving the efficiency of air-water contact below the film fill is to dispose splash fill in the form of conventional spaced horizontal plates mounted on stringers below the film fill in the path of the inlet air. A system of this type is described in Henning, U.S. Pat. No. 3,643,931. Although this system does improve the air-water contact below the film fill, the spaced horizontal plates which extend across the entire area below the film fill create significant resistance to the air as it is drawn upwardly into the film fill. This resistance is increased when such splash fill substantially interferes with air travelling into the inboard or central region of the tower.
Phelps U.S. Pat. No. 3,917,764, suggests an excellent way to improve the efficiency of the distribution of air onto film fill by sloping the film fill so that the air entering the tower horizontally need not turn any extreme angles from the horizontal to the vertical. However, as disclosed, this system is not used in combination with a conventional tower utilizing horizontally disposed film fill.
Conventional splash fill horizontal air flow towers generally include a slight slope (e.g., 10.degree. from the vertical) to counteract the effect of the drift inwardly of the gravitating water caused by the cross-flow of the air in a generally horizontal direction. See, e.g., column 3, lines 47-59 of Fordyce U.S. Pat. No. 2,776,121.